Field of the Invention
The present invention relates to an imaging device and a method of driving imaging device.
Description of the Related Art
In an imaging device, when a still image is photographed, generally, a focus adjustment is performed by using an auto focus (hereinbelow, referred to as “AF”) which has widely been known hitherto and the photographing is performed. On the other hand, when a moving image is photographed, since all actions which are performed when a focus is adjusted to a certain object to be photographed are recorded as a part of the moving image, there is also a case where it is desired to perform a focus adjustment by a manual focus (hereinbelow, referred to as “MF”) without using AF.
By performing the focus adjustment by MF, the user can photograph a video image while moving a lens at an arbitrary speed up to an in-focus position. However, in dependence on a photographing situation, there can be also a case where it is difficult to perform the focus adjustment by MF or MF cannot be used. In such a case, although such a request that the user wants to photograph by using AF is also presumed, the focus adjustment can be performed only by a uniform lens driving which has been predetermined on the camera side.
Under such a background, Japanese Patent Application Laid-Open No. 2012-173531 proposes an imaging device which performs such focus control that a driving speed of a focus lens is decided based on operation information of the user and the focus lens is moved at the decided focus lens driving speed. Japanese Patent Application Laid-Open No. 2013-178323 proposes an imaging device in which an in-focus speed of the lens is changed based on a judgment of the user.
However, according to the techniques disclosed in Japanese Patent Application Laid-Open No. 2012-173531 and Japanese Patent Application Laid-Open No. 2013-178323, such an operation that the lens driving speed to the object is raised or reduced or the like is merely performed. Therefore, for example, such a fine desire of the user that although the lens driving speed is raised at the time of a large blur, at a position near an in-focus point, the lens driving speed is reduced and the lens is smoothly in-focused cannot be reflected. Unlike AF of the still image, according to AF in the moving image, since the lens driving itself until the in-focus state is inherently reflected, the lens driving itself at the time of AF becomes a part of a product. Therefore, if a fine setting according to a scene to be photographed can be made, it is desirable when a video image closer to a user's desired video image is photographed.